Amid the recent reconciliatory mood on the Korean Peninsula, crimes involving sales of defunct North Korean money are on the rise in China and Southeast Asia.

According to South Korea's National Intelligence Service(NIS) on Thursday, international crime rings in parts of Southeast Asia have been attempting to sell old North Korean bills on the premise that their value will jump once the North denuclearizes and its economy develops.

They have been approaching victims, offering to sell the bills 30 to 40 percent cheaper than their value.

Most of the bills were issued before Pyongyang's currency reforms in 2009 and are no longer in use.

The spy agency said a crime organization was caught trying to exchange five million won worth of the bills in Thailand last month, and recently a South Korean businessman there received an offer to buy 200 million won worth of bills.

The agency warned although South Koreans are mostly reluctant to possess North Korean money, international crime rings likely have their eyes set on South Korean nationals.

In cooperation with the Foreign Ministry, the NIS plans to post warnings on Web sites of South Korean diplomatic missions.

[Photo : KBS News]